IN SITU OBSERVATIONS TEST HYPOTHESES of FUNCTIONAL MORPHOLOGY in MASTIGOTEUTHIS (CEPHALOPODA, OEGOPSIDA) C Roper, M Vecchione

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IN SITU OBSERVATIONS TEST HYPOTHESES OF FUNCTIONAL MORPHOLOGY IN MASTIGOTEUTHIS (CEPHALOPODA, OEGOPSIDA) C Roper, M Vecchione

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C Roper, M Vecchione. IN SITU OBSERVATIONS TEST HYPOTHESES OF FUNCTIONAL MOR- PHOLOGY IN MASTIGOTEUTHIS (CEPHALOPODA, OEGOPSIDA). Vie et Milieu / Life & En- vironment, Observatoire Océanologique - Laboratoire Arago, 1997, pp.87-93. hal-03103507

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IN SITU OBSERVATIONS TEST HYPOTHESES OF FUNCTIONAL MORPHOLOGY IN MASTIGOTEUTHIS (CEPHALOPODA, OEGOPSIDA)

C.F.E. ROPER 1, M. VECCHIONE2 1 Department ofInvertebrate Zoology, National Muséum of Natural History, Smithsonian Institution, Washington, D.C. 20560, USA 2 National Marine Fisheries Service, Systematics Laboratory, National Muséum of Natural History, Washington, D.C. 20560, USA

CEPHALOPODS ABSTRACT. - Mastigoteuthis magna observed in situ has a characteristic "tuning SQUID fork" posture that can be used as an aid for identification, even for very small SUBMERSIBLE squids. Observations of living Mastigoteuthis from submersibles in the western DEEP SEA BEHAVIOR Atlantic Océan enabled us to test formerly proposed hypothèses concerning FUNCTIONAL MORPHOLOGY functional morphology of thèse deep sea squids. Hypothèses supported by observations on live animais include : 1) The large fins provide propulsion ; simple and double sinusoïdal waves move anteriorly or posteriorly, fins flap powerfully, fins roll together ventrally to squeeze water out anteriorly or posteriorly. 2) Tentacular suckers have weak release mechanism ; tentacular clubs on live animais feel very sticky, like fly paper, and must be firmly pulled off observer's skin and aquarium wall. 3) Tentacular suckers have sensory function ; tentacular tips skim along bottom to allow animal to maintain position in food-rich benthic boundary layer. Observations do not support thèse hypothèses : 1) Vacuolated arms and head induce head-upwards posture; observations confirm a head-downwards posture maintained by constantly maneuvering fins. 2) Ventral arms lock together to form "gutter" for feeding ; live animais hold long ventral arms far apart with proximal part of tentacles enveloped in tentacular sheaths, allowing them to serve as non-tangling trolling lines fishing for minute prey. 3) Well developed eyes and ink sac indicate photic zone habitat ; ail observations of Mastigoteuthis from submersibles are close to the bottom below 500 m, never in photic zone. We suggest Mastigoteuthis evolved from a Chiroteuthis-like ancestor; its adaptive characters enable it to inhabit the unique trophic zone immediately above the deep sea bottom, feeding on small zooplankters with trolled, non-tangling tentacles.

CEPHALOPODES RÉSUMÉ. - Mastigoteuthis magna se présente in situ en posture de "diapason" CALMAR caractéristique permettant l'identification de l'espèce, même lorsqu'il s'agit SUBMERSIBLE d'individus de petite taille. L'observation de Mastigoteuthis à partir d'un EAUX PROFONDES COMPORTEMENT submersible mis en action dans l'Atlantique occidental a permis de tester certaines MORPHOLOGIE FONCTIONNELLE hypothèses avancées précédemment, relatives à la morphologie fonctionnelle de ces Calmars des eaux profondes. Les hypothèses confortées par nos observations sont : 1) Les très grandes nageoires servent à la propulsion : des ondes sinusoïdales simples et doubles se propagent en direction antérieure ou postérieure, les nageoires battent vigoureusement, et s'enroulent du côté ventral en chassant l'eau vers l'avant ou vers l'arrière. 2) Les ventouses des tentacules ont un faible mécanisme de relaxation : les massues tentaculaires d'individus vivants sont très adhésives, comme du papier collant ("bandes à mouches"), et résistent fortement à toute traction exercée pour les détacher de la peau d'un observateur ou de la paroi d'un aquarium. 3) Les ventouses tentaculaires ont une fonction sensorielle : les extrémités des tentacules sont traînées au contact du fond permettant ainsi à l'animal de se maintenir dans la couche limite du benthos, riche en nourriture. Les observations ne confortent pas les hypothèses suivantes : 1) Les bras et la tête contenant des vacuoles causent l'orientation de la tête vers le haut : les observations mettent en évidence une position dans laquelle la tête est orientée vers le bas, maintenue ainsi par le mouvement continu des nageoires. 2) Les bras ventraux sont réunis pour former une "gouttière" canalisant la nourriture vers la bouche : les animaux vivants tiennent leurs bras ventraux écartés l'un de l'autre, les parties proximales des tentacules étant enveloppées dans des gaines tentaculaires, de sorte que les tentacules servent de lignes de pêche traînées pour ■88 C.F.E. ROPER, M. VECCHIONE la capture de proies minuscules. 3) Les yeux et la poche d'encre bien développés témoignent d'un habitat en zone euphotique : toutes les observations sur Mastigoteuthis ont été faites près du fond, à des profondeurs dépassant 500 m, donc en aucun cas dans la zone euphotique. Nous pensons que Mastigoteuthis s'est développé à partir d'un ancêtre de type Chiroteuthis ; ses caractéristiques adaptatives lui permettent de vivre dans la zone trophique très particulière qui se trouve juste au-dessus du substrat des grands fonds, et de consommer du zooplancton de petite taille à l'aide de tentacules séparés et traînés.

INTRODUCTION MATERIALS AND METHODS

Direct observations on the functional morphology of deepsea cephalopods always have been The information on M. magna was gathered from hampered by the difficulty of access to animais several sources, principally from video tapes taken du- that are functioning normally. As a resuit, most ring dive cruises in the western Atlantic Océan using the Johnson-Sea-Link I and // submersibles. Also, spé- inferences about function have been based on stu- cimens were captured and identified after having been dies of the anatomy of dead spécimens. Ongoing observed in situ. The most extensive observations and exploration of deepsea environments using sub- videos were made during the cruise to "The Point" area mersibles is slowly overcoming this problem by near Cape Hatteras, North Carolina in September 1994. allowing accumulation of observations on cepha- The bottom topography in the région of the dive sites lopods in situ and by enabling their gentle capture at The Point at 700-1 000 m consists of soft sédiments for prolonged observation in shipboard aquaria. in a séries of ridges and canyons that fan out into deeper The research reported here continues the séries water. Températures at the bottom in the canyons were generally 4.5°C. Détails of the dive sites and ecosystem of studies we are conducting on deep sea cepha- in relation to the cephalopod project are given in Roper lopods observed in situ from manned and unman- and Vecchione (1996). Eight separate in situ video ned submersibles, e.g., Vecchione and Roper séquences that range in duration from a few seconds (1992), Vecchione et al. (1992), Roper and Vec- to about 15 minutes were recorded during the 1994 chione (1996). We have compiled from a number cruise. Also during this cruise, one of the spécimens of sources several detailed observations on Mas- observed in situ was captured by the submersible, main- tigoteuthis spp, especially M. magna Joubin, tained alive and videotaped for several hours in a 1 m 1913. A submersible cruise off North Carolina in diameter plankton kreisel aquarium (Hamner, 1990). 1994 provided a particularly rich source of M. magna behavior captured on video tape. Chun (1910) first described the internai anato- OBSERVATIONS my of several species of immature Mastigoteu- this; Dilly et al. (1977) provided excellent detailed observations on the anatomy of trawl-captured The accumulation of video séquences of Mas- Mastigoteuthis sp. from which they inferred func- tigoteuthis magna during the past several years tional capabilities. Our observations from submer- has revealed a strikingly habituai posture consis- sibles on living Mastigoteuthis in their natural tently seen in this species. This posture typically habitat enable us to test several hypothèses consists of the animal hanging or hovering head concerning functional morphology proposed by downward with the mantle vertical, posterior up- Dilly et al. (1977), most notably the following : ward, head oblique, arms I through III held at an oblique angle toward the horizontal (approxima- 1. Based on the vacuolated tissue of the arms, tely 45°) ; the ventral arms (IV) and the tentacles, the squid probably lives with its head upwards. their proximal sections tightly wrapped in the 2. Because of the large and complex magno- tentacular sheaths of arms IV, hang down verti- cellular lobe of the brain, it is likely that propul- cally in a tuning fork (inverted Y with curved sion is accomplished mainly by the large fins. arms) configuration so that the arms and tentacles 3. The large ventral arms may be held together are rather widely separated (Plate I. A-F). The to form a "gutter" for feeding. tentacle length of the seven spécimens that could be measured extended 3-4 times the length of the 4. The tentacular suckers probably have a poor mantle (Plate I. B,C,F). No active swimming or or slowly acting release mechanism. jetting is associated with the hovering posture, 5. The multitude of minute tentacular suckers which appears to be held for extended periods of may have a sensory function. time. Spécimens are in that posture when first 6. The well-developed eyes and ink sac suggest encountered, continue through periods of obser- that at least some of the adult life is spent in the vation and filming of up to 15 minutes, and photic zone where the eyes are used for the dé- remain essentially immobile as the submersible tection of prey. départs. OBSERVATIONS TEST HYPOTHESES OF FUNCTIONAL MORPHOLOGY 89

Pl. I. - Mastigoteuthis magna : A, In typical head-down posture. Fins show double sine wave undulation. Mucous strands (white blobs) attached to posterior end of mantle. B, In typical head-down, tuning fork posture with tips of elongate tentacles hanging close to bottom. Fins show non-synchronous double sine wave undulation. Note shadow on bottom. C, Drifting just above bottom in typical head-down, tuning fork posture. Elongate tentacles and their shadow on bottom are converging. Fins in double sine wave undulation. D, Drifting just above bottom in typical head-down, tuning fork posture with elongate tentacles and their shadows converging on the bottom. E, Drifting in typical tuning fork posture through expanded tentacles of anémone. F, In typical tuning fork posture with tentacles greatly elongate as animal suddenly drifts over steep drop-off of sea floor. 90 C.F.E. ROPER, M. VECCHIONE

The animal's position in the water column and almost completely into the tentacular sheaths of its vertical orientation are maintained by either arms IV (Plate II. A,F), possibly for protection, simple or complex undulations of the fins. The to reduce drag and to avoid tangling. undulations of the fins may take one of several An observation for which we have as yet no forms, depending on the correction required to satisfactory explanation is the occurrence of what maintain vertical orientation, élévation above the appear to be mucus strands attached principally, bottom and, perhaps, orientation relative to the but not exclusively, around the posterior end of current. Thèse include single sinusoidal undula- the mantle (Plate I. A, II. B). While this is not tions that originate at the anterior end of the fins observed on every spécimen, it occurs frequently and proceed posteriorly to the posterior end enough on Mastigoteuthis, as well as on Histio- (Plate II. A), and those that originate at the pos- teuthis, to draw our attention. terior tip of the fins and proceed in a single wave to the anterior edge of the fins (Plate II. B). A The stomach contents of several muséum spé- new undulation begins after the completion of the cimens were examined. The stomach is lined with a very heavy, rugose, cuticular lining. Several preceding one. Each fin seems individually con- trolled, because the frequency and amplitude on stomachs contained a large quantity of yellow oil. Some stomachs contained a few bits and pièces one fin is différent from that of the other. that consisted of the céphalothorax and spines of Complex undulations include a double sine wave progressing along the fin simultaneously (Plate I. unidentified copepods. The caecum is a very large, long organ in comparison to the size of the sto- A,B,C); thèse tend to be much more rapid than mach and does not have a similar lining. the single waves, and they may move either posteriorly or anteriorly. The undulations are used for relatively gentle motions that are positional cor- rections, not substantial locomotion. The fins also DISCUSSION can be flapped in a strong dorsalventral beat (Plate II. C), apparently with a posterior to ante- The work of Dilly et al. (1977) provides an rior gradient, that imparts a tailfirst locomotion excellent platform from which to discuss the in that can be relatively strong when only the fins situ observations of Mastigoteuthis magna. Thèse are involved; a very rapid escape reaction occurs authors give a detailed description of the histology when strongly flapped fins are combined with of the brain and aspects of the external and in- water ejected (jetted) from the funnel. ternai anatomy of Mastigoteuthis sp., and they Another, previously unknown, function was ob- utilize thèse data to formulate hypothèses about served for the fins. The fins sometimes are rolled its habits and mode of life. Our observations on together ventrally so that they overlap along the living animais enable us to test their hypothèses ventral midline and squeeze the water between about functional morphology. the fins and mantle out anteriorly or posteriorly, 1. Vacuolated tissues of arms and head induce providing a sort of low-velocity jet propulsion head upwards posture. - Most of the tissues of (Plate I. D,E). Mastigoteuthis, especially the arms, head and The M. magna we have observed in the typical mantle are vacuolated and contain lightweight am- tuning fork posture have nearly always been lo- monium ions as an aid to buoyancy (Denton and cated near the sea floor (Plate I. B-F). The animais Gilpin-Brown 1973). Because the ventral arms are drift along slowly above the bottom with their so very large, consequently buoyant, Dilly et al. tentacles trailing down towards the substrate, and (1977) hypothesized that thèse animais live with occasionally the tentacular tips touch the bottom. their heads and arms vertically upwards when they This is clear in several video séquences in which are not swimming. The tentacles, on the other the tentacular tips and their shadows converge on hand, are not vacuolated but have dense tissue, the bottom sédiment (Plate I. C,D). One séquence so they hang downwards. Our observations on live recorded over a bottom that steeply deepens animais do not support the headup posture. Ins- shows the animal elongating its tentacles to twice tead, Mastigoteuthis consistently use their fins their length as the sea floor drops off below it actively to maintain the inverse position, with (Plate I. F). In cases where the bottom is not seen head, arms and tentacles downwards. One squid in the video, dive data show that the submersible that had ceased undulating its fins briefly began and the Mastigoteuthis are just a few meters above rotating toward a headup position, but this was the substrate. In the kreisel, the tentacular clubs an exception, possibly caused by the squid being of the squid stuck tenaciously to the glass, even in water disturbed by the submersible's maneuve- when the animal vigorously tried to swim away, ring. stretching the tentacles to many times the length 2. Propulsion by large fins. - Because the ma- of the mantle before they pulled free. When an gnocellular lobe of the brain is extremely wellde- animal is not drifting along the bottom with ten- veloped with its motor control output going to the tacles extended, the tentacles are contracted large fins, Dilly et al. (1977) deduced that the OBSERVATIONS TEST HYPOTHESES OF FUNCTIONAL MORPHOLOGY 91 13 Ai la

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Pl. II. - Mastigoteuthis magna : A, With single sinusoidal undulation of fins originating at anterior end. Animal somewhat above bottom with tentacles contracted into tentacular sheaths of arms IV. B, With single sinusoidal undulation originating at posterior end. Mucous strands (white blobs) attached to posterior tip of mantle. C, With fins overlapping ventrally and motionless. Note rotation of head upward. D, With fins rolling together along ventral midline, squeezing water out posteriorly in a low-velocity jet. E, With fins overlapping along ventral midline at completion of low-velocity jetting stroke. F, In non-trolling mode off the bottom with right tentacle (left in photo) nearly completely contracted into tentacular sheath of right arm IV and left tentacle being contracted and enveloped into left arm IV tentacular sheath. 92 CEE. ROPER, M. VECCHIONE

fins are the main source of propulsion for Masti- cells that detect prey and direct it to the arms for goteuthis. This inference is further supported by transfer to the mouth. We have no observations the very well-developed fin lobe that receives on actual prey capture, but we observed one ani- connections from the magnocellular lobe (Young mal drifting just above the bottom in the feeding 1977; Maddock and Young 1987). Our in situ mode we hypothesize ; it seemed to monitor its observations strongly support this hypothesis and distance above the bottom with its tentacles. When demonstrate the numerous, complex, and varied the bottom dropped off suddenly, the tentacles fin functions. Single and double sinusoidal wave immediately elongated to twice their length. This undulations sweep anteriorly or posteriorly along may resuit from a strong neural association be- the fins ; fins flap powerfully in escape maneu- tween the tentacular suckers, the magnocellular vers ; fins roll together ventrally to squeeze water lobe and the fins (Dilly et al. 1977 ; Young 1977), out both anteriorly or posteriorly. Jet propulsion and it would keep the animal in the feeding zone does occur through the funnel, but the fins always of concentrated zooplankton in the benthic bound- seem active and are dominant in both locomotion ary layer (Dauvin et al, 1995). and position-holding. 6. Well-developed eyes and ink sac indicate 3. Ventral arms form gutter for feeding - Fol- photic zone habitat. - Dilly et al. (1977) hypo- io wing the suggestion of Rancurel (1971), Dilly thesize that the large, well-developed eyes and an et al. (1977) concur that the large ventral arms ink sac indicate that thèse animais undergo diel may be held together by the suckers to form a vertical migration into the photic zone in search gutter that captures prey. The observations and of prey. None of the numerous in situ observations videos of live animais show that the arms virtually we now have on several species of Mastigoteuthis always are held far apart. The tentacular sheaths have occurred in the photic zone ; ail observations along the entire length of the ventral arms envelop from submersibles are very close to the bottom. the proximal section of the tentacles, holding them Roper and Young (1975) presented data on verti- far apart, perhaps so the tentacles will not become cal distribution of trawl-captured mastigoteuthids, entangled and stuck together with their multitude some by closing nets, and no captures of adults of minute suckers. Therefore, the large, long arms occurred in the photic zone. Shea (1995) showed function to control the position of the tentacles, the same pattern for paralarval mastigoteuthids holding them as far apart as possible while they caught in closing plankton nets. Mastigoteuthids drift along near the bottom like sticky trolling always have been considered deep-sea inhabitants, Unes fishing for minute prey. mesopelagic to bathypelagic in vertical distribu- 4. Tentacular suckers have weak release mecha- tion. The first hint we had that at least some nism. - Dilly et al. (1977) suggest that the extremely species are in fact benthopelagic came when sto- numerous, minute, pedunculate tentacular suckers mach contents of macrourid rattail fishes (Cory- that consist primarily of cuticular tissues with very phenoides) were shown regularly to include Mas- little soft or muscular tissue, function to mechani- tigoteuthis and Histioteuthis beaks and remains cally attach to prey, but that they are very weak and (CEE. Roper, pers. observ.). Thèse fishes are slow to release their grip. This would explain why benthic/nearbottom feeders that do not venture far many trawlcaptured spécimens have their tentacles off the bottom. This révélation that mastigoteu- missing ; they have been pulled off in the webbing thids are nearbottom dwellers, in spite of the of the net from which they could not be released. longheld assumption of their midwater habitat, When a live Mastigoteuthis is handled, its tentacles shows that caution is required when inferring feel very sticky, reminiscent of fly paper, and they function from anatomy in the absence of ancillary have to be firmly pulled off the skin, as they do data on habitat, behavior or ecology. not release themselves. The hypothesis is further An alternative explanation for the large eyes borne out by our observations in the shipboard could be that vision is used to detect biolumines- kreisel aquarium, where the clubs stuck tenaciously cence stimulated by movement of predators. It is to the glas s while the animal tried to move away, not known yet if the ink sac secrètes luminescent stretching the tentacles to many times the length of ink as has been observed in some other deep sea the mantle before they release. While other squids cephalopods (Herring 1977), or if the ink sac show this sticking phenomenon, e.g., Chiroteuthis, merely is a remnant of a shallow water ancestor they do not appear to do so to the extrême that (Vecchione 1994). Mastigoteuthis does (M. Vecchione, CEE. Roper, It seems counterintuitive that thèse squids ty- pers. observ.). pically are seen in a posture in which the center 5. Tentacular suckers have sensory function. — of gravity is higher than the center of buoyancy, A very large axial nerve along the tentacle because of the energy required to maintain this connects directly into the large ventral magnocel- position. We suggest the possibility that the Mas- lular lobe, the complexity of which suggests a tigoteuthidae evolved from a Chiroteuthis-like an- chemotactile function. Dilly et al. (1977) propo- cestor. We have seen Chiroteuthis, which has sed that tentacular suckers may contain sensory smaller fins than Mastigoteuthis and vacuolated tis- OBSERVATIONS TEST HYPOTHESES OF FUNCTIONAL MORPHOLOGY 93 sues in its large head and arms, floating in an DAUVIN J.-C, SORBE J.-C. and LORGERE J.-C. oblique head-upward orientation with the tentacles 1995. Benthic boundary layer macrofauna from the trailing downward. The mastigoteuthids have de- upper continental slope and the Cap Ferret canyon veloped large, dexterous fins and complex magno- (Bay of Biscay). Oceanologica Acta 18 : 113-122. cellular lobes to reverse the passive Chiroteuthis DENTON E.J. and GILPIN-BROWN J.B. 1973. Floa- posture resulting from buoyancy. This allows them tation mechanisms in modem and fossil cephalo- to use the sheathed ventral arms for better control pods. Adv. mar. Biol. 11 : 197-268. of the tentacles with their extremely numerous, highly DILLY P.N., NIXON M. and YOUNG J.Z. 1977. Mas- sensitive suckers. This complément of characters tigoteuthis - the whip-lash squid. J. ZooL, Lond. enables the mastigoteuthids to inhabit the unique 181 : 527-559. trophic zone immediately above the deepsea bottom and to take advantage of the small zooplankters FELLEY J.D. and VECCHIONE M. 1995. Assessing habitat use by nekton on the continental slope using concentrated there (Wishner, 1980) while avoiding archived videotapes from submersibles. Fish. Bull. accidentai entanglement of the tentacles. 93 : 262-273. It is acceptable, even necessary, to infer func- HERRING P.J. 1977. Luminescence in Cephalopods tion based on morphology of dead spécimens, but and Fish. In : Nixon M. and Messenger J.B., Eds. in order to inspire confidence, thèse inferences The Biology of Cephalopods. Symp. Zool. Soc. must be treated as hypothèses to be tested. Ob- Lond. 38 : 127-160. servations of live animais in their natural habitat allow tests of such hypothèses. HAMNER W.M. 1990. Design development in the plankton kreisel, a plankton aquarium for ships at Because of the characteristic posture reported sea. J. Plant Res. 12 (2) : 397-402. here, animais seen at the limits of vision from the MADDOCK L. and YOUNG J.Z. 1987. Quantitative submersible and in videotapes and photographs différences among the brains of cephalopods. J. can now easily be identifiée! as mastigoteuthids, ZooL, Lond. 212 : 739-767. even very small juvéniles. In one instance, we have RANCUREL P. 1971. Mastigoteuthis grimaldi (Joubin, a one-second séquence from a transect reported on 1895). Chiroteuthidae peu connu de l'Atlantique tro- by Felley and Vecchione (1995) of a squid in the pical (Cephalopoda-Oegopsida). Cah. O.R.S.T.O.M. typical position that allows us to identify it as a sér. Océanogr. 9 (2) : 125-145. Mastigoteuthis. One séquence is available on video ROPER CEE. and VECCHIONE M. 1996. In situ because the observer in the submersible thought observations on Brachioteuthis beanii Verrill : paired that, from a distance, the very small juvénile Mas- behavior, probably mating (Cephalopoda, Oegopsi- tigoteuthis was a cydippid ctenophore with its two da). Am. Malac. Bull. 13 : 55-40. tentacles hanging downward. ROPER CEE. and YOUNG R. 1975. Vertical distribution of pelagic cephalopods. Smiths. Contr. Zool. 209 : 1-51. Portions of the video séquences upon which this paper are based are presented in the "Cepha- SHEA E.K. 1995. The Early Life Historiés of Three lopods in Action" web pages at the following URL Families of Cephalopods (Order Teuthoidea) and an Examination of the Concept of a Paralarva. Masters on the Internet, http ://www.nmnh.si.edu/cephs. Thesis, School of Marine Science, Collège of Wil- ACKNOWLEDGMENTS. - We gratefully acknowledge the liam and Mary, Virginia, 133 p. following people and organizations for their significant VECCHIONE M. 1994. Systematics and the lifestyle contributions to this work : Drs. E. Widder, T. Frank, and performance of cephalopods. Mar. Fresh. Behav. and T. Bailey for inviting one of us (CFER) to parti- Physiol. 25 : 179-191. cipate in their cruise (National Science Foundation Grant Number OCE-9313872, National Underwater VECCHIONE M., ROBISON B.H. and ROPER CEE. Research Program Grant Numbers UNCW 9410 and 1992. A taie of two species : tail morphology in UNCW 9406) ; the scientific, submersible and ship's paralarval Chiroteuthis (Cephalopoda : Chiroteuthi- crews ; Harbor Branch Océanographie Institution, Ft. dae). Proc. Biol. Soc. Wash. 105 (4) : 683-692. Pierce, Florida, which owns and opérâtes the submer- VECCHIONE M. and ROPER CEE. 1992. Cephalo- sible and its mother ship, R/V Edwin C. Link; Woody pods observed from submersibles in the Western Lee, Smithsonian Marine Station ; Dane Penland, Office North Atlantic. Bull. Mar. Sci. 49 (1-2) : 433-445. of Photo Services, Smithsonian Institution ; the Smith- WISHNER K.F. 1980. Aspects of the community eco- sonian Marine Station, Dr. M. Rice, Director; M.J. logy of deep-sea, benthopelagic plankton, with spé- Sweeney prepared the plates and reviewed the manu- cial attention to gymnopleid copepods. Mar. Biol. script. Two anonymous reviewers are acknowledged 60: 179-187. with thanks. This paper is Smithsonian Marine Station Contribution Number 397. YOUNG J.Z. 1977. Brain, Behavior and Evolution of Cephalopods. In Nixon M. and Messenger J.B., Eds. The Biology of Cephalopods. Symp. Zool. Soc. LITERATURE CITED Lond. 38 : 377-434. CHUN C. 1910. Die Cephalopoden. 1. Teil : Oegopsida. Wissenschaftlichen Ergebnisseder Deutschen Tiefsee Reçu le 14 février 1996; received February 14, 1996 Expédition "Valdivia" 18: 1-402. Accepté le 3 juin 1996 ; accepted June 3, 1996